Technical Field
This invention relates to development stations in electrostatographic reproduction apparatus, and more particularly to a mounting system which includes a dual axis displacement mechanism in such a station for lifting the development unit thereof.
Electrostatographic process apparatus, which for example produce or reproduce toned images on selected substrates by employing electrostatic charges and toner particles on an insulated photoconductive surface, typically operate through a sequence of currently well known steps. These steps include (1) charging of the insulated photoconductive surface with electrostatic charges, (2) forming a latent image electrostatically on such surface by selectively discharging areas on such surface, (3) developing the electrostatic image so formed with particles of toner, (4) transferring the toned image to a suitable substrate for fusing thereon to form a permanent record, and (5) cleaning by removing residual toner and/or other particles from the photoconductive surface in preparation for similarly producing another image.
The quality of the images produced by such apparatus depends, in part, and significantly so, on the ability to precisely locate a development unit of the apparatus relative to the image-bearing member, as well as on regularly and easily servicing and replacing such a development unit. Various devices and mechanisms have therefore been developed for mounting, moving and supporting a development unit relative to the image-bearing member of such apparatus. Such devices and mechanisms are disclosed for example in U.S. Pat. Nos. 3,953,121 issued to Reichart et al on Apr. 27, 1976 ; 4,841,330 issued to Owada et al on Jun. 20, 1989 ; 4,866,482 issued to Hirasawa et al on Sep. 12, 1989 ; and 4,963,936 issued to Carter on Oct. 16, 1990. Unfortunately, in addition to cost, the mounting, as well as the loading and unloading of the development unit relative to the image-bearing member are ordinarily sources of problems and difficulties for such devices and mechanisms. On the one hand, complex and elaborate such devices and mechanisms are expensive and difficult to operate. On the other hand, the very simple one of such devices and mechanisms ordinarily do not independently interface the development unit with the image-bearing member and consequently, the development unit in each such case is not easy to load and unload as above. Therefore, serious problems such as overloading against the image-bearing member, and toner dusting may be experienced. In either case, precise loading of the development unit relative to the image-bearing member and easy serviceability are sources of difficulties, and usually the quality of images developed suffers.